Leaking Injector Signs

[BlackBox]

Hi all,

I have been having a few problems with my R34 gtt.

If I leave the car off for 4+ hours it will either a) start then stall and start back up fine or b) start then run rough for a second and then it's fine.

I have tried priming the fuel pump a few times with the ignition before starting bit it didn't fix the problem.

Also if I leave it idle for a minute then give it a rev it will blow a lot of white smoke for a second

I have recently gas tested the exhaust and it was very high for hydrocarbons (unburnt fuel)

I am thinking the injectors may be leaking but after some confirmation, who would people recommend to rebuild them? They are nismo 770cc.

Edited December 14, 2013 by BlackBox

[White GTS-T]

I would be doing the following:

Put a fuel pressure gauge on it, turn the engine off and clamp off the fuel lines. if the pressure starts to drop, your injectors are leaking.

Although white smoke wouldn't be indicative of a leaking injector.

Remove the spark plugs and inspect for oil, your valve stem seals may be leaking. While the plugs are out, pressure test the cooling system. Wait and then crank it over. If there is any signs of coolant, you have a head/gasket problem.

Good luck.

[BlackBox]

Haven't been using any coolant so I'm hoping it's not a head/gasket problem. I have ordered an inline fuel gauge and cooling system pressure tester so I can do those test when they arrive.

Also the Pcv valve hose running to the manifold gets sucked shut at idle, then puffs out like normal at the slightest crack of the throttle, the Pcv valve has been cleaned and is functioning so I'm thinking the hose may have perished and is too soft.

[White GTS-T]

Failing that, a compression test and leak down test may be required to narrow down the problem. Let us know how you get on.

[Marcus89]

Have you bought the car recently or owned for a long time and it's only just started doing this?

I have a similar problem that is caused by my lack of a 1 way valve on my fuel pump. When cold for some reason it is happy to prime and start up straight away but if I drive somewhere turn car off and go to turn it back on in 30+ mins I need to crank the engine like a normal start, stop and then crank again then it will start nicely. I feel for me it is due to a form of vapor with most of the fuel in my lines draining back to tank and the fuel that is left warming up and becoming a gas as I have had no other issues.

[BlackBox]

i have only recently noticed it. although i have also recently installed a plazmaman manifold where i removed one of the fuel dampners/regulators, so im not sure if this could have an effect.

[Black4DR]

vacuum air leak

[533 RYC]

Bingo!

You more than likely hit the nail on the head & found the answer to your problem.

Is there anyway you can refit the dampener/regulator you removed?

[BlackBox]

I could refit it but I would rather leave it off if possible, really trying to get a clean engine bay,

I have an adjustable sard fpr so I was under the impression the standard items were of no use..

I also just purchased a plazmaman fuel rail which I think eliminates the other damper mounted on the standard rail.

If this is the cause could it be rectified by fitting a check valve or adjusting the fpr

[Black4DR]

I just changed my plenum and it was doing the exact same thing, Tps was just a fraction out ( .58v ) so I set that again and I reset my idle. seems good now.

[BlackBox]

Cheers mate, I did set the the tps voltage but I will definitely re-check..

[Black4DR]

Yeah I set mine too, but they dont seem to take much of a knock to upset them. I also grabbed the wheel on the throttle body and turned it. It wasnt fully closed so when I had set it up before it wasnt set with the throttle on the stop haha. so I cleaned the butterfly too.